There are a wide variety of fired heaters used in refinery and chemical processing units. These can be classified in various ways. For example, they can be classified according to the heat exchanger mechanisms, i.e., whether the heaters consist solely of a radiant section or includes a convection section. The heater can also be classified according to the arrangement of the heat exchange tubes, i.e., whether they are arranged horizontally or vertically within the heater.
The present invention is concerned with heaters which have a separate convection section above a radiant section and which convection section contains rows of heat exchange tubes horizontally disposed within the convection section. Such fired heaters as generally referred to as horizontal tube fired heaters. In such heaters corbelling is used to prevent gas bypassing between the side wall and the tubes disposed in the convection section of the heater. Typically the corbelling is a fixed rigid member constructed of steel or refractory that is attached to and extends horizontally outwardly from the sidewall of the convection section of the heater. Unfortunately, the corbelling obstructs modular placement of tube bundles within the convection section of the heater. Also, the corbelling severely limits in situ repair of the sidewall refractory.
It is an object of the present invention to provide a corbelling which overcomes the deficiencies of the corbelling of the prior art.